Please note, I have already placed bids on your other, identical jobs. This is an ideal project for a simple VBA macro. I will write the macro and run it on your data, to produce an error-free list of matches, and record the number of matches to bad email addresses. On completion of the assignment, I will provide you with the macro code - which you will then be free to use if this task is ever required again in the future! In fact, I have already written a very similar VBA macro, but of course I will adapt it to match your particular dataset. A bit about me: I have extensive experience writing VBA macros in Microsoft Word and Excel for UK government agencies.